Multi-ply paper forming machine with upward and downward forming runs

ABSTRACT

A machine for making multi-ply paperboard including first, second, third, and fourth looped forming wires with each of the looped wires having guide means therein to form a first vertical run between the first and second wires dewatering the web formed therebetween in both directions with the wires trained through a generally curved path by engaging the second wire with a series of bars extending in a cross-machine direction and spaced in a machine direction so that the wires inscribe a series of chords through the arc, similar bars within the third and fourth wires with headboxes arranged to deliver stock to the head end of the first forming run and to deliver stock onto one side of the web at the beginning of the second forming run and onto the other side at the end of the third forming run with the outer layers of stock dewatered in their direction and the plies interlocking due to the pressure of the forming wires and arrangement of the runs.

United States Patent Roell MUlL'lll-PLY PAPER FORMING MACHINE WllTH UPWARD AND DOWNWARD FORMllNG RUNS [75] Inventor: William J. lRoell, Beloit, Wis.

[73] Assignee: Beloit Corporation, Beloit, Wis.

[22] Filed: June 4, 1973 [21] Appl. No: 365,993

[52] 11.8. C1 162/299, 162/300, 162/352 [51] llnt. Cl. D211 1/00 [58] Field of Search 162/299, 300, 303, 304,

[56] References Cited UNITED STATES PATENTS 2,977,277 3/1961 Kelly l 162/303 X 3,471,367 10/1969 Chupka.... 162/303 3,543,834 12/1970 Stuebe 162/300 3,597,315 8/1971 Notbohm et a1 162/303 X 3,726,758 4/1973 Parker et al. 162/299 3,752,734 8/1973 Notbohm 162/299 Primary ExaminerS. Leon Bashore Assistant Examiner-Richard V. Fisher Attorney, Agent, or Firm-Hill, Gross, Simpson, Van Santen, Steadman, Chiara & Simpson [57] ABSTRACT A machine for making multi-ply paperboard including first, second, third, and fourth looped forming wires with each of the looped wires having guide means therein to form a first vertical run between the first and second wires dewatering the web formed therebetween in both directions with the wires trained through a generally curved path by engaging the second wire with a series of bars extending in a crossmachine direction and spaced in a machine direction so that the wires inscribe a series of chords through the are, similar bars within the third and fourth wires with headboxes arranged to deliver stock to the head end of the first forming run and to deliver stock onto one side of the web at the beginning of the second forming run and onto the other side at the end of the third forming run with the outer layers of stock dew-atered in their direction and the plies interlocking due to the pressure of the forming wires and arrangement of the runs.

5 Claims, 1 Drawing Figure BACKGROUND OF THE INVENTION The invention relates to improvements in paper making machines, and more particularly to improvements in multi-ply paper machine forming sections. In the forming of multi-ply boards, the interlocking or adherence of the layers of the web to each other is very important. This is particularly true when the board is made at higher forming speeds and with different types of stock. It has been discovered that an important factor in the interlocking of the layers of the web to each other is the interspersement or interlocking of the short fibers from one layer to the other. Various mechanisms have been provided to attempt to improve this interlocking between layers, which have limiting factors which incorporate disadvantages.

It is accordingly an object of the present invention to provide an improved multi-ply board forming machine which can operate at relatively high speeds and pro vides an improved product with the layers more strongly interlocked to each other to increase the quality and strength of the board.

One manner in which multi-layer boards have heretofore been made is to form the layers separately, such as on cylinder machines, and place the layers together after being formed. With the arrangement, the layers tend to be independent of each other and do not adhere to each other with sufficient strength. This lack of strength can cause separation of the layers while the board is being made or when it is used, and results in boards of inferior strength. The more rigidly each layer can be bonded to the adjacent layer, the greater the overall unitary strength of the board, so that with very good bonding, a substantially monolithic board results. This is particularly important where the quality and nature of the different layers of board vary substantially and each layer is formed because of its own inherent properties, i.e., inexpensiveness of the stock, ink receptivity, color and so forth.

A further object of the invention is to provide an improved multiply board forming machine wherein the layers are formed while in contact with a previously formed layer so that an optimum possibility is provided for interlocking of the fibers between layers, and the layers are not merely laid together after being formed.

A still further object of the invention is to provide a multi-ply board forming mechanism wherein the layers are successively formed in a unique manner so that the short fibers from adjacent layers intersperse during the dewatering operation, resulting in a monolithic multiply board of improved strength.

A still further object of the invention is to provide improved structure which more readily accommodates forming the layers of multi-ply board of varying types of stock wherein outer layers of improved quality may be employed to improve the overall quality and appearance of the board.

A still further object of the invention is to provide an improved multi-ply board forming machine which is capable of operating at higher speeds than machines heretofore available and particularly at substantially higher speeds than cylinder machines.

Other objects, advantages and features, as well as equivalent structures which are intended to be covered herein, will become more apparent with the teachings of the principles of the invention in connection with the disclosure of the preferred embodiment in the specification, claims, and drawings, in which:

DESCRIPTION OF THE DRAWINGS The single FIGURE of the drawings shows a side elevational view in somewhat schematic form of a multiply web forming section of the paper making machine constructed and operating in accordance with the principles of the present invention.

DESCRIPTION The structure includes a first forming wire 10 cooperatively arranged with a second forming wire 11. The second forming wire is cooperatively arranged with a third forming wire 12 which is cooperatively arranged with a fourth forming wire 13.

The first and second looped forming wires 10 and 11 are supported by guide means which train the wire into a first forming run 14 which preferably extends vertically upwardly. Ahead of the run is a forming throat 18 which receives the stock directed thereto from a head box 17 which has a slice opening that delivers the stock in a jet into the forming throat 18. The stock in this case will be of the type to form the intermediate layer of the finished board and will normally be of a lower grade stock to provide the filler and bulk for the center layer.

After the intermediate layer is formed. it is carried on the second wire down into a second forming run 15 which is preferably vertical and extends downwardly. Stock is delivered onto the upper surface of the intermediate layer by the slice opening of a headbox 19 which directs the stock downwardly into a forming throat 20. This second outer layer is dewatered in the second forming run 15 and is then carried on the third wire 12 into a third forming run 16 which is preferably vertically upwardly. Stock is delivered onto the outer and opposite surface of the intermediate layer by a headbox 21 which delivers stock in a spouting jet into a forming throat 22 and leads to a vertical forming run 16. Thus, the finished layers of stock are positioned first on one side and then on the other side of the intermediate layer, and the layers are dewatered while in contact with the intermediate layer with the dewatering occurring through the newly formed layer but in such a manner so as to encourage interspersement of the fine fibers between the layers. This is accomplished by the forming runs being shaped in a general arcuate path, but formed of a series of straightline chords so that a pressure point occurs between the wires at each of the points of engagement with the wire, as will become clear with further description herein. These pressure points will cause a surging back and forth of the water within the stock and an interspersement between fine fibers between the layers. Since the newly formed layers are dewatered outwardly, the fines will tend to collect on the upper surface, that is, the surface next to the intermediate layer where they can perform their best bonding operation. Yet, the structure is such that it encourages continued dewatering through the outer surface of the previously formed web, thus permitting some additional dewatering to occur and further encouraging the forming of a firm bond between layers. The carrying of the web through gentle bending arcs first in one direction and then in the opposite direction while dewatering also encourages more firm interlocking between the layers.

Turning again to the first dewatering run 14, the throat 18 into which the stock is directed from the headbox 17 is formed between an open roll 26 and a solid roll 27. The open roll may be of the suction type, but preferably is a roll with grooves on its outer periphery. As the stock travels upwardly between the two wires in the forming run 14, water is expressed through both the first and second wires. Water expressed through the first wire is skimmed off the surface of the wire by blades 24 and 25, and the water is received in a saveall 31. Another saveall 32 receives water passing through bars or blades 23.

The linear tension in the first wire 11) is adjustable by an adjustable guide roll 30 and with increase or decrease in tension, the amount of lateral pressure applied to the web throughout its forming run 14 is controlled.

Within the second wire 11 throughout the forming run 14, a series of blades or bars 23 which extend in a cross-machine direction, engage the inner surface of the second wire. These bars have spaces in between to receive water expressed from the web and push both the first and second wires laterally of the path between the breast roll 27 and an upper couch roll 28. Thus, the wires which are tensioned between these rolls, will engage the edges of the bars 23 and extend in straightline chords between them with the points of contact generally lying on an arc. At each of the points of contact with the edges of the bars, a pressure point will occur between the wires, and the pressure on the water in the fibers at that location tends to release the water and express it from the web. The upper breast roll 28 has a suction gland therein to urge the web to follow the second wire as it turns toward the second forming run 15. The first wire has a breast roll 29 therein positioned above the breast roll 27 so that the first wire wraps the second wire at the end of the forming run with some water being expressed from the web in the turn around the suction breast roll 27.

In the second vertical forming run 15, the entry throat for receiving the stock from the headbox 19 is formed between breast rolls 33 and 34. Breast roll 33 is an open roll such as a roll with grooves and 34 is a solid roll.

The web with the fresh layer of stock on its outer surface travels downwardly through the second forming run, and the third wire 12 is engaged by a series of cross-machine extending bars 35. These bars are spaced apart in the machine direction to provide spaces therebetween for receiving the water which is caught in a savewall 36. With the intermediate web which was formed in the first forming run, and the outer layer which has now been added to the intermediate web, both traveling in a vertical direction, as the water is expressed from the newly formed layer, it can pass back and forth between the layers without being affected by gravity. A small additional amount of water may be expressed through the intermediate layer, but in the second run primarily dewatering is occurring in the newly added layer.

The second wire wraps a lower suction couch roll 38 within the third wire 12 at the end of the forming run carrying the web therebetween. The web being drawn to the third wire 12 by the suction couch roll 28 will follow the third wire 12 in the horizontal run as the second wire 11 is separated therefrom and travels down over a turning roll 39.

A tension roll 37 is positioned within the second wire and its lineal tension is controllable to control the pres sure between the wires along the second forming run 15.

For entering the third forming run 16, the wires are trained over breast rolls 40 and'41, with 40 being an open roll and 41 being a solid roll. The wires are pressed laterally of their path of travel between the breast roll 41 and an upper suction couch roll 43 by cross-machine extending vertically spaced bars 42. These bars have the same effect on the third forming run 16 by forcing the wires to travel through a general arcuate path, but inscribed by a series of chords because the points of contact are spaced and positioned in a general arcuate path. Water expressed from the outer layer which has been added tothe two previously formed layers is received by a saveall 48. Again, the fibers on the newly formed layer are encouraged to move back and forth in the surface of the newer formed layer and the intermediate layer due to the action of the spaced bars forming pressure points between the wires. As the wires travel upwardly, they travel around the suction couch roll 43 and a third wire is wrapped around the turn by a breast roll 44 within the third wire 12. The three-layered web follows the fourth wire 13 in a downwardly inclined path to be picked off the wire by a pickup roll 45 carrying a pickup felt 46.

A wire tension roll 47 within the fourth wire 13 adjusts its tension. Primarily, the tension between the wires in the fourth forming run 16 and consequently the pressure between the wires is controlled by a tensioning roll 49 within the third wire 12.

The present machine is capable of forming a multiply web within a much shorter shop space than was possible with structures heretofore which had to be stretched out in a horizontal direction across the shop floor. The vertical formation also contributes to the control of the dewatering and control of the location of the fines to enhance the bond between the various plies. The mechanism could be used to form a two-ply web or three-ply as shown, or additional forming runs may be provided to form additional layers in certain circumstances.

I claim as my invention:

1. A multi-ply board making machine comprising in combination:

first and second looped forming wires;

first and second wire guide means training the wires into a first vertically upwardly extending forming throat leading to a first vertically upwardly extending dewatering run with the wires applying a pressure against a web through said run;

a first headbox positioned to direct a pressure jet of first stock into the first throat;

first and second water receiving means within said first and second loops respectively receiving water expressed from the web in said first run;

a third looped forming wire;

a third wire guide means within the third wire positioned to guide the wire into a vertically downwardly extending second forming throat leading to a vertically downwardly extending second dewatering run with the second wire and the second and third wire applying pressure to the web through said second run; 

1. A multi-ply board making machine comprising in combination: first and second looped forming wires; first and second wire guide means training the wires into a first vertically upwardly extending forming throat leading to a first vertically upwardly extending dewatering run with the wires applying a pressure against a web through said run; a first headbox positioned to direct a pressure jet of first stock into the first throat; first and second water receiving means within said first and second loops respectively receiving water expressed from the web in said first run; a third looped forming wire; a third wire guide means within the third wire positioned to guide the wire into a vertically downwardly extending second forming throat leading to a vertically downwardly extending second dewatering run with the second wire and the second and third wire applying pressure to the web through said second run; a second headbox directing a second stock into said second throat onto the web carried on the second wire from the first run thereby forming a second layer on the web; and a water receiving means within the third wire receiving water from said second layer with the first and second layers being bonded to each other by the flow of water during the second run; each of said forming runs including a series of successive spaced bars extending in a cross-machine direction sequentially engaging the second wire in the first forming run and the third wire in the second forming run, said bars lying in a broad arc of very large radius so that the first and second wires in the first forming run and the second and third wires in the second forming run travel through a plurality of chordal sectors and the web is gently dewatered in both directions in the first run and the second layer is gently dewatered in both directions in the second run so as to cause a bonding between the second layer and first layer.
 2. A multi-ply board making macHine constructed in accordance with claim 1: and including a fourth looped forming wire; fourth wire guide means within the fourth wire positioned to guide the wire into a third vertically upwardly extending forming throat leading to a third vertically upwardly extending dewatering run formed with the third wire and with said third and fourth wires applying a pressure to the web throughout said second run; a third headbox directing a third stock onto the opposing side of the first layer of the web as it is carried on the third wire; and a fourth water receiving means within the fourth wire receiving water from the third layer with the layers being bonded to each other by the flow of water during the third run, the water receiving means within the fourth wire including a plurality of successive spaced bars extending in a cross-machine direction sequentially engaging the fourth wire with their wire engaging edges lying in a broad arc so that the third and fourth wires travel through a plurality of chordal sectors and the third layer is gently dewatered in both directions forming a bond with the first layer.
 3. A multi-ply board making machine constructed in accordance with claim 1: and including means for controlling the tension of each of said wires so as to control the pressure between the wires through said runs.
 4. A multi-ply board making machine constructed in accordance with claim 2: and including means for controlling the tension of each of said wires for controlling the pressure between wires through said runs.
 5. A multi-ply board making machine constructed in accordance with claim 4: and including a mechanism for picking the web off of the fourth wire after said third forming run. 